Biomedical subjects

Romina Mizrahi

Publications and source records attributed to Romina Mizrahi.

11 recordsLinked to original sources

PubMed2025

Human development, inequality, and their associations with brain structure across 29 countries.

BACKGROUND: The macro-social and environmental conditions in which people live, such as the level of a country's development or inequality, are associated with brain-related disorders. However, the relationship between these systemic environmental factors and the brain remains unclear. We aimed to determine the association between the level of development and inequality of a country and the brain structure of healthy adults. METHODS: We conducted a cross-sectional study pooling brain imaging (T1-based) data from 145 magnetic resonance imaging (MRI) studies in 7,962 healthy adults (4,110 women) in 29 different countries. We used a meta-regression approach to relate the brain structure to the country's level of development and inequality. RESULTS: Higher human development was consistently associated with larger hippocampi and more expanded global cortical surface area, particularly in frontal areas. Increased inequality was most consistently associated with smaller hippocampal volume and thinner cortical thickness across the brain. CONCLUSIONS: Our results suggest that the macro-economic conditions of a country are reflected in its inhabitants' brains and may explain the different incidence of brain disorders across the world. The observed variability of brain structure in health across countries should be considered when developing tools in the field of personalized or precision medicine that are intended to be used across the world.

Humans↗

PubMed2006

The effect of antipsychotic treatment on Theory of Mind.

BACKGROUND: Deficits in a patient's 'theory of mind' (TOM) have been proposed to lead to psychosis. However, it remains unclear whether TOM deficits constitute a trait- or a state-related deficit and whether they respond to antipsychotic treatment, and also whether the change in TOM and change in psychosis are associated. METHOD: In the cross-sectional component of this study, 71 patients with psychotic disorders were included and TOM ability was measured using a hinting task in which subjects had to infer real intentions behind indirect speech. In the longitudinal study, a different cohort of 17 drug-free patients were included wherein they received antipsychotic treatment for 6 weeks and the effect on psychotic symptoms and TOM was measured every 2 weeks. Associations between TOM and psychopathology were assessed and a mixed effects model was used to investigate the rate of change over time. RESULTS: Positive and Negative Syndrome Scale (PANSS) total scores were significantly associated with TOM scores. The hinting task was not associated with positive symptoms but was significantly associated with negative and general symptoms. The longitudinal arm of the study showed that both PANSS positive scores and TOM improved after medication was started, particularly during the first 2 weeks of antipsychotic treatment, but these changes were not associated. The TOM response at 2 weeks of antipsychotic treatment reached similar values to those obtained in the cross-sectional sample. CONCLUSIONS: Although TOM and psychotic symptoms are related to each other, antipsychotic treatment impacts each independently, suggesting a dissimilar cognitive or neurobiological substrate for the two.

Adult↗

PubMed2006

The selective effect of antipsychotics on the different dimensions of the experience of psychosis in schizophrenia spectrum disorders.

While most standard symptom scales regard the 'psychotic' or 'positive' dimension of schizophrenia as a single factor, several lines of evidence suggest that psychosis itself is a multidimensional phenomenon. The foregoing literature suggested at least five distinct dimensions to psychosis; to test this, we developed, validated and applied an instrument to measure these dimensions and then applied it to examine the effect of antipsychotics on the different dimensions of the psychotic experience. The Dimensions of Psychosis Instrument (DIPI) was administered to 91 psychotic patients with schizophrenia spectrum disorders and a confirmatory factor analyses (CFA) was carried out to examine the five dimensions: cognitive preoccupation (CP) with the psychotic experience; emotional involvement (EM); behavioural impact (BI) of the experience; conviction (CO) in it; emotional; and external perspective (EP) about the experience. In a separate cohort of 17 prospectively treated patients, the impact of antipsychotics on these dimensions was assessed. BI showed the greatest improvement (32%) at 2 weeks, while CP and emotional improved somewhat less (22% and 14%, respectively). Improvement in CO was limited (6%) while EP showed no change. These results suggest that over the first few weeks of treatment, antipsychotics rapidly reduce the behavioural impact of the principal psychotic symptom and decrease cognitive and emotional preoccupation with it, without greatly altering the patients' conviction in or perspective about their psychotic experience.

Adolescent↗

PubMed2006

Binding characteristics and sensitivity to endogenous dopamine of [11C]-(+)-PHNO, a new agonist radiotracer for imaging the high-affinity state of D2 receptors in vivo using positron emission tomography.

[11C]-(+)-PHNO (4-propyl-9-hydroxynaphthoxazine) is a new agonist radioligand that provides a unique opportunity to measure the high-affinity states of the D2 receptors (D2-high) using positron emission tomography (PET). Here we report on the distribution, displaceablity, specificity and modeling of [11C]-(+)-PHNO and compare it with the well characterized antagonist D2 radioligand, [11C]raclopride, in cat. [11C]-(+)-PHNO displayed high uptake in striatum with a mean striatal binding potential (BP) of 3.95 +/- 0.85. Pre-treatment with specific D1 (SCH23390), D2 (raclopride, haloperidol) and D3 receptor (SB-277011) antagonists indicated that [11C]-(+)-PHNO binding in striatum is specific to D2 receptors. Within-subject comparisons showed that [11C]-(+)-PHNO BP in striatum was almost 2.5-fold higher than that measured with [11C]-(-)-NPA ([11C]-(-)-N-propyl-norapomorphine). Comparison of the dose-effect of amphetamine (0.1, 0.5 and 2 mg/kg; i.v.) showed that [11C]-(+)-PHNO was more sensitive to the dopamine releasing effect of amphetamine than [11C]raclopride. Amphetamine induced up to 83 +/- 4% inhibition of [11C]-(+)-PHNO BP and only up to 56 +/- 8% inhibition of [11C]raclopride BP. Scatchard analyses of [11C]-(+)-PHNO and [11C]raclopride bindings in two cats showed that the Bmax obtained with the agonist (29.6 and 32.9 pmol/mL) equalled that obtained with the antagonist (30.6 and 33.4 pmol/mL). The high penetration of [11C]-(+)-PHNO in brain, its high signal-to-noise ratio, its favorable in vivo kinetics and its high sensitivity to amphetamine shows that [11C]-(+)-PHNO has highly suitable characteristics for probing the D2-high with PET.

Amphetamine↗

PubMed2006

How antipsychotics work-from receptors to reality.

How does a small molecule blocking a few receptors change a patients' passionately held paranoid belief that the FBI is out to get him? To address this central puzzle of antipsychotic action, we review a framework linking dopamine neurochemistry to psychosis, and then link this framework to the mechanism of action of antipsychotics. Normal dopamine transmission has a role in predicting novel rewards and in marking and responding to motivationally salient stimuli. Abnormal dopamine transmission alters these processes and results in an aberrant sense of novelty and inappropriate assignment of salience leading to the experience of psychosis. Antipsychotics improve psychosis by diminishing this abnormal transmission by blocking the dopamine D2/3 receptor (not D1 or D4), and although several brain regions may be involved, it is suggested that the ventral striatal regions (analog of the nucleus accumbens in animals) may have a particularly critical role. Contrary to popular belief, the antipsychotic effect is not delayed in its onset, but starts within the first few days. There is more improvement in the first 2 weeks, than in any subsequent 2-week period thereafter. However, a simple organic molecule cannot target the complex phenomenology of the individual psychotic experience. Antipsychotics diminish dopamine transmission and thereby dampen the salience of the pre-occupying symptoms. Therefore, in the initial stage of an antipsychotic response, the patients experience a detachment from symptoms, a relegation of the delusions and hallucinations to the back of their minds, rather than a complete erasure of the symptoms. Only with time, and only in some, via the mediation of new learning and plasticity, is there a complete resolution of symptoms. The implications of these findings for clinical care, animal models, future target discovery and drug development are discussed.

Animals↗

PubMed2006

Phenomenology and clinical correlates of delusions in Alzheimer disease.

OBJECTIVES: The objectives of this study were to determine whether anosognosia, depression, and elevated mood are associated with delusions in Alzheimer disease (AD), and to examine the validity of standardized diagnostic criteria for psychosis of dementia. METHOD: The authors assessed a consecutive series of 771 patients with AD attending a dementia clinic with a comprehensive neuropsychologic and psychiatric evaluation that included specific measures of delusions, hallucinations, anosognosia, depression, and elevated mood. RESULTS: Delusions were found in one-third of the patients and hallucinations in 7%. Most patients with hallucinations also had delusions. A principal component analysis of the Psychosis Dementia Scale, which rates the presence and severity of delusions, produced the factors of paranoid misidentification and expansive delusions. Paranoid, but not expansive, delusions increased across the stages of the illness. Anosognosia and depression were significantly and independently associated with the presence of delusions, whereas elevated mood was significantly associated with expansive, but not paranoid, delusions. A multiple logistic regression analysis demonstrated that delusions in AD were significantly associated with depression, anosognosia, overt aggression, and agitation. CONCLUSIONS: Anosognosia, depression, global cognitive deficits, and elevated mood are the main psychiatric correlates of paranoid misidentification and expansive delusions in AD, whereas overt aggression and agitation are the most frequent behavioral concomitants of psychosis in AD.

Aged↗

PubMed2006

Depression in Alzheimer's disease.

Depression is one of the most frequent comorbid psychiatric disorders in Alzheimer's disease and other dementias, and is associated with poorer quality of life, greater disability in activities of daily living, a faster cognitive decline, a high rate of nursing home placement, relatively higher mortality and a higher frequency of depression and burden in caregivers. Depression in Alzheimer's disease is markedly under-diagnosed and most patients with depression are either not treated or are on subclinical doses of antidepressants. Recent randomized controlled trials have demonstrated the efficacy of sertraline and moclobemide to treat depression in Alzheimer's disease. Other psychoactive compounds may be useful as well, but careful consideration must be given to potentially serious side effects.

Alzheimer Disease↗

PubMed2005

From dopamine to salience to psychosis--linking biology, pharmacology and phenomenology of psychosis.

How does an excess in a neurochemical lead someone to being paranoid about the intentions of their neighbour? And why does blocking a dopamine receptor improve this symptom? In this article we present a heuristic framework which attempts to link the biology, phenomenology and pharmacology of psychosis. Focussing on dopamine's role in reward prediction and motivational salience we propose that psychosis arises from an aberrant assignment of novelty and salience to objects and associations. Antipsychotics block dopamine receptors and decrease dopamine transmission, which leads to the attenuation of aberrant novelty and salience. This 'salience' framework accounts for existing data and questions several current assumptions about the speed of onset phenomenological effects of antipsychotics and their behavioral effects in animal models. We review new data to show that in contrast to the prevailing idea of a "delayed onset" of antipsychotic action, the improvement is evident in the first few days. Antipsychotics do not eradicate symptoms, but create a state of "detachment" from them. And the actions of antipsychotics in the conditioned avoidance response model, one of the best established animal models for identifying antipsychotic action, are consistent with the idea that they dampen aberrant as well as normal motivational salience. The article discusses the caveats, limitations as well as the clinical implications of the salience framework.

Antipsychotic Agents↗

PubMed2005

How antipsychotics work: the patients' perspective.

BACKGROUND: While much is known about the neuropharmacology and objective efficacy of antipsychotics, little is known about how these drugs act on psychosis from the patients' perspective. Most previous studies of the patient's perspective have focused on drug tolerability and acceptability-rather than their effects on psychosis per se. METHODS: The authors examined how antipsychotics work from a patient's perspective by analyzing their responses to a subjective questionnaire. Ninety-one patients with schizophrenia (cross-sectional component) and eight neuroleptic naïve patients (before and after treatment, longitudinal component) participated. The patients' responses to the questionnaire were analyzed using Principal Component Analysis (PCA) and general linear models. RESULTS: Analysis of the patients' responses showed that from their perspective the drugs were substantially more effective in: "help deal, help stop thinking, and make the symptoms not bother" rather than "take away" or "change my mind". This differentiation was clear in the raw data and was supported by a formal PCA. Two underlying factors-the first termed detachment and second eradication-explained 71% of the variance in the patients' perspective on how antipsychotics work for them. Neuroleptic naïve patients, who had no prior exposure, expected drugs to help with both detachment and eradication, but, changed their mind with just 6 weeks of experience with the medications. CONCLUSIONS: From the patients' perspective the action of antipsychotics is best characterized by a detachment from symptoms-rather than an eradication or elimination of symptoms. They have more wide-ranging expectations prior to antipsychotic exposure, but, even 6 weeks of exposure is sufficient to change their mind in favor of detachment. This finding is consistent with some of the very earliest ideas that antipsychotics produced a state of "indifference" and is also consistent with the more recent, neurobiologically informed notions that antipsychotics work by dampening the salience of psychotic symptoms.

Adolescent↗

PubMed2005

Specificity of symptoms of depression in Alzheimer disease: a longitudinal analysis.

OBJECTIVE: Authors examined the temporal stability of symptoms of major and minor depression and apathy in dementia. METHODS: A consecutive sample of 65 patients with Alzheimer disease (AD) and depression at baseline evaluation received a follow-up psychiatric assessment that included the Structured Clinical Interview for DSM-IV and the Hamilton Rating Scale for Depression an average of 17 months later. RESULTS: Half of the sample had no depression at follow-up, and showed a significant improvement in sadness, guilt, suicidal ideation, disruption in sleep, loss of interest, loss of energy, thoughts of death, social withdrawal, psychomotor changes, changes in appetite/weight, and symptoms of anxiety. No significant changes were found on scores of irritability or apathy. CONCLUSIONS: The study demonstrates the specificity of depressive symptoms in AD and suggests that apathy and depression are different behavioral domains.

Aged↗

PubMed2005

The construct of minor and major depression in Alzheimer's disease.

OBJECTIVE: This study examined the frequency of major and minor depression in Alzheimer's disease and determined whether these types of depression have a different functional and psychopathological impact and whether there is a change in the prevalence of major and minor depression throughout the stages of Alzheimer's disease. METHOD: A consecutive series of 670 patients with probable Alzheimer's disease were assessed with the Structured Clinical Interview for DSM-IV; specific instruments to rate the presence and severity of depression, anxiety, apathy, irritability, delusions, pathological affective crying, performance of activities of daily living, and social functioning; and a standardized neuropsychological evaluation. Diagnoses of major and minor depression were generated from DSM-IV criteria. RESULTS: Twenty-six percent of the patients had major depression, 26% had minor depression, and 48% were not depressed. Major depression was significantly associated with sad mood in all three stages of the illness, although this association dropped significantly for minor depression in severe Alzheimer's disease. Both major and minor depression were significantly associated with more severe psychopathology, functional impairments, and social dysfunction. Depressive symptoms that most strongly discriminated between Alzheimer's disease patients with and without sad mood were guilty ideation, suicidal ideation, loss of energy, insomnia, weight loss, psychomotor retardation/agitation, poor concentration, and loss of interest. CONCLUSIONS: Our study demonstrates that DSM-IV criteria for major and minor depression identify clinically relevant syndromes of depression in Alzheimer's disease, mild levels of depression can produce significant functional impairment, and the severity of psychopathological and neurological impairments increases with increasing severity of depression.

Activities of Daily Living↗